"The standard mileage rate for transportation or travel expenses is 54 cents per mile for all miles of business use (business standard mileage rate).... The standard mileage rate is 14 cents per mile for use of an automobile in rendering gratuitous services to a charitable organization under Section 170.... The standard mileage rate is 19 cents per mile for use of an automobile [1] for medical care described in Section 213, or [2] as part of a move for which the expenses are deductible under Section 217."